A like rotary electrical switch is known from German examined patent application No. 20 36 775. It is composed of a rotary button, two contact bridges, a circuit plate, a compression spring and a disc. In the assembled condition of the rotary switch, the spring draws the pin through the disc downwardly away from the circuit plate so that, as a result, the contact bridges are pressed resiliently against the circuit plate by the rotary button.
It is to be considered less favorable in this rotary switch that, since the hole diameter of the disc is slightly smaller than the external diameter of the pin, relatively great mounting forces are caused during mounting with the end of urging the disc for the purpose of its positive retaining engagement over the pin into the groove therefor provided. This necessitates special mounting tools which entail higher costs. Apart from the increased mounting efforts needed, likewise the spring representing a special piece part has adverse effects on the costs for the rotary switch.
Moreover, the balls designed at the two ends of the contact bridges as well as the bipartite design render the manufacture of the contact bridges costly which, in the embodiment herein illustrated, must be made either as turned pieces or a shaped parts.
What is to be regarded as another shortcoming is the functionability of the rotary switch, wherein on each switch actuation the balls of the contact bridges slide out of the bores furnished in the circuit plate what may cause premature damage to the frequently very thin circuit plate. Likewise the displacement of the rotary button in its axial direction during a switching action is a disadvantage.
Therefore, it is the object of the present invention to devise a rotary electrical switch which is composed of as few components as possible, requires little mounting space and costs, which permits a quick and simple assembly and which, beside its great reliability in operation, affords much ease of handling.